Roof support assemblies suitable for use in mines



p 13, 1966 m. H. H. BOLTON ET'AL. 3,272,0M

ROOF SUPPORT ASSEMBLIES SUITAELE FOR USE IN MINES Filed May 13, 1965 2Sheets-Sheet 1 I ii ii INvEN-ro2 3 pa ulLAg H. H. BaLT 'N BY F/ A NKPAM/LIN ila/(ASL. c Parr S p 1966 D. H. H. BOLTON ETAL. 3,272,084

ROOF SUPPORT ASSEMBLIES SUITABLE FOR USE IN MINES Filed May 13, 1965 2Sheets-Sheet 2 s v N a W w m a L s w w 1 H m A c A TH N H L 3 n h N 6 mm A m u R l urn y B United States Patent "ice 3,272,084 RQQE SUPPORTASSEMBLIES SUHTABLE EUR USE TN MINE? Douglas Herbert Hewlett Bolton,Winchcomhe, Frank l'awling, Charlton Kings, and Michael Charles Potts,Presthury, England, assignors to Dowty Mining Equipment Limited FiledMay 13, 1965, Ser. No. 455,541 Claims priority, application GreatBritain, May 15, 1964, 20,382/64 7 Claims. (Cl. 91--414) This inventionrelates to roof support assemblies suitable for use in mines.

The present invention provides a roof support assembly including aseries of advanceable roof supports, each roof support having at leastone fiuid-pressure-operated prop operable to set the support against aroof and a fluidpressure-operated jack operable to advance the support,each roof support also having a valve assembly controlling the operationof the prop and the jack, the valve assembly being operated by thereceipt of a signal from the preceding roof support .in the series tocause its roof support to undergo an advancing operation, and the valveassembly being responsive to the satisfactory completion of theadvancing operation of its roof support to send a signal to the nextroof support in the series, and bypassing means operable from a positionremote from the roof supports to cause the signal to be sent from oneroof support to the next roof support in the event of failure of theroof support to satisfactorily complete an advancing operation.

Each valve assembly may include a first valve associated with a linewhich remains unpressurised until its roof support receives the signalfrom the preceding roof support, and operation of the by-passing meansactuating the first valve of every valve assembly, each valve assemblybeing so arranged that a first valve actuated by the by-passing meanscauses the signal to be sent to the next roof support if the lineassociated with the first valve is pressurised.

Each valve assembly may include a second valve operated by asatisfactory roof-supporting fluid pressure in the prop of its roofsupport, after the roof support has undergone an advancing operation, tocause the signal to be sent to the next roof support, and the actuationof the first valve of a valve assembly when the line associated with thefirst valve is pressurised causing the operation of the second valve ofthe valve assembly.

The signal may be a fluid-pressure signal which supplies the fluidpressure for the line.

The present invention also provides a roof support assembly including aseries of advanceable roof supports, each roof support having at leastone fluid-pressureoperated prop operable to set the support against aroof and a fiuid-pressure-operated jack operable to advance the support,each roof support also having a valve assembly controlling operation ofthe prop and the jack, each valve assembly including an operating linewhose pressurisation by fluid under pressure causes operation of theprop and of the jack, and a secondary valve assembly connected by afirst signal line to the secondary valve assembly of the adjacent roofsupport in one direction along the series and by a second signal line tothe secondary valve assembly of the adjacent roof support in theopposite direction along the series, each secondary valve assemblyincluding a first one-way valve which allows 3,27Zfi84l Patented Sept.13, 1966 pressurisation of the operating line from the first signal linewhen the first signal line is pressurised from the relevant adjacentroof support and a second one-way valve which allows pressurisation ofthe operating line from the second signal line when the second signalline is pressurised from the other adjacent roof support, and valvemeans responsive to the satisfactory completion of the advancingoperation of its roof support to hold the first and second one-wayvalves in a closed position to prevent pressurisation of the operatingline from either signal line and to connect a source of fluid pressureto the first and second signal lines.

The valve means may include two valves which can be manuallyalternatively operated to pressurise either signal line and hold theassociated one-way valve in a closed position.

The pressure in the operating line may drain away when there is nopressure in either signal line and when both one-way valves are held inthe closed position.

One embodiment of the present invention will now be described, by way ofexample, with reference to the accompanying drawings of which,

FIGURE 1 is a diagrammatic view of a series of advanceable roof supportarranged along the working face of a coal-mine,

FIGURE 2 is a diagrammatic view of three roof supports of the series,showing the hydraulic connections to each roof support and,

FIGURE 3 is a diagrammatic view of the hydraulic circuit of one of theroof supports.

With reference to the accompanying drawings, a series of roof supports 1are arranged along the working face 2 of a coal-mine. Each roof support1 includes a floorengaging member 3 which carries threehydraulicallyoperated props 4, and the three props 4- carry aroofengageable member (not shown). Each roof support 1 is connected to asnakeable conveyor 5 by a hydraulically-operated jack 6 operable toadvance the roof support 1 toward the conveyor 5. Some roof supports,for example every fourth roof support as shown, have a secondhydraulically-operated jack 7 which is operable to apply an advancingforce to the conveyor 5 when its roof support is set against the roof.However, this invention is not concerned with the advance of theconveyor 5, and the operation of the jacks '7 will not be furtherdescribed here. The jacks 7 may operate in the manner described in UK.patent application No. 34,818/ 63. FIGURE 1 also shows a cutting machine8 which is moving from left to right along the Working face 2.

A main hydraulic pressure line 9 extends along the series of roofsupports and is connected to a valve assembly 10 of each roof support bya branch line 11. A control line 12, which can be pressurised to varioushydraulic pressures for purposes which will be described later, alsoextends along the series of roof supports, and is connected to the valveassembly 10 of each roof support by a branch control line 13.

Each valve assembly 10 includes a secondary valve assembly 14- which isconnected to the secondary valve assembly 14- of the adjacent roofsupport by a signal line 15. Each secondary valve assembly 14 includestwo valves 16, 17 which can be opened by linear movement of push-rods18, 19. The push-rods 18, 19 can be moved to open valves 16, 17 byhydraulic pressure in a chamber 21 acting on pistons 22, 23 carried bypush-rods 18, 19, in which case both valves 16, 17 are opened together.The push-rods 18, 19 can also be moved by manual operation of apivotally-mounted lever 23, in which case the valves 16, 17 can beopened alternatively, depending upon the direction of movement of thelever 24. The push-rods 18, 19 also carry valves 25, 26 respectively.Each signal line 15 is connected to a position between the valves 16, 25or 17, 26 as the case may be.

The secondary valve assembly 14 also includes two valves 29, 31 to oneof which one signal line 15 is connected and to the other of which theother signal line 15 is connected. When open, the valves 29, 31 bringthe respective lines 15 into communication with a line 32 leading to thejack 6. Each valve 29, 31 carries a piston 33, 34 respectively, uponwhich acts a spring 35, 36 respectively, in the valve-closing sense.Each signal line 15 also includes a non-return valve 37, 38respectively. The valve 29 is connected to its signal line 15 on theside of the non-return valve 37 remote from the secondary valve assembly14, and the portion of the signal line 15 on the side of the non-returnvalve 37 adjacent the secondary valve assembly 14 is connected to thepiston 33 so that pressure in this portion of the signal line 15 acts onthe piston 33 in the same sense as the spring 35. The valve 31 issimilarly connected to its signal line 15.

When the valve 16 is shut and valve 25 is open, as shown in FIGURE 3,the non-return valve 37 connected to the left hand side of the secondaryvalve assembly 14 is put into communication with a chamber 27 connectedto a fluid return line 30 and fluid does not flow through the non-returnvalve 37 into the signal line 15. When valve 16 is open and valve 25 isshut, the non-return valve 37 connected to the left hand side of thesecondary valve assembly 14 is put into communication with a chamber 28connected to the branch supply line 11, and fluid from this branchsupply line flows through the non-return valve 37 into the signal line15. In practice, valves 16 and 25 will be so arranged that valve 25 cannever be partly open when valve 16 is partly open so that chamber 28 cannever be in communication with chamber 27. The signal line 15 andnon-return valve 38 connected to the right hand side of secondary valveassembly 14 is connected to valves 17, 26 which operate in a similarmanner to valves 16, 25 respectively.

The line 32 passes through a self-latching by-pass valve 39, anon-return valve 41 and a drain valve 42. The by-pass valve 39 is a twoposition valve which opens a line 32 in one position and, in its otherposition, shuts off the valves 29, 31 from the non-return valve 41 andconnects valves 29, 31 through line 43 and non-return valve 44 to asequence valve 45. The by-pass valve 39 is springbiased to the firstposition, shown in the drawing, and can be moved to its second positionby a predetermined pressure in the branch control line 13, to which itis connected.

Line 32 is also connected through a prop re-setting valve 46 to a line47 including a non-return valve 48 and a pressure reducing valve orrestrictor 49. Line 47 is connected to the props 4 through non-returnvalves 51 and lines 52. Prop re-setting valve 46 can be opened bycontraction of the jack 6 to almost its minimum length, or by apredetermined pressure in branch control line 13.

Lines 52 are also connected through non-return valves 53 to a line 54leading to a prop-release valve 55 and a pressure relief valve 56.Prop-release valve 55 is operable by a pivotally-mounted lever 57, as isalso a manual prop-setting valve 58, connected to branch supply line 11and line 47. The lever 57 is operable by a piston 59 actuated bypressure in line 32, and by a piston 61 actuated by pressure in line 47.

A line 62 connected to the portion of line 47 between valve 49 andnon-return valves 51 includes a non-return valve 63 and is connected tothe sequence valve 45. A locking valve 64 connected to line 62 betweensequence valve 45 and non-return valve 63 can be opened by apredetermined pressure in branch control line 13. A

portion of branch control line 13 connected to chamber 21 of secondaryvalve assembly 14 includes the sequence valve 45 and a safety valve 65which can be closed by a predetermined pressure in branch control line13.

The drain valve 42 includes a piston valve 66 urged by a spring 67 to aposition in which the portion of line 32 between the drain valve 42 andthe jack 6 is isolated from the return line 30. The piston valve 66contains a nonreturn valve 68 through which fluid can pass from theby-pass valve 39 to the jack 6. A restrictor 69 is connected to theportion of line 32 between the non-return valve 41 and the drain valve42 and to the fluid return line 30.

The various elements in each valve assembly 10 which are operated bypredetermined pressures in the control line 12 and branch control line13 are arranged to be operated by different predetermined pressures. Inthis embodiment, the pistons 22, 23 of secondary valve assembly 14require a pressure of 400 lbs/sq. in. in chamber 21 to cause the pistons22, 23 to shut valves 25, 26 and open valves 16, 17. The safety valve 65shuts when the pressure reaches 800 lbs/sq. in. The prop re-settingvalve 46 opens at a pressure of 1,200 lbs/sq. in., and the locking valve64 is opened by a pressure of 2,800 lbs/sq. in.

When the conveyor 5 has been advanced, the roof supports 1 can be causedto undergo advancing operations either automatically one after theother, or each roof support 1 can be caused to undergo an advancingoperation by manual operation of the lever 24 of the secondary valveassembly 14 of the roof support 1 on either side of the roof support 1to be advanced, as will be described later.

Firstly, the operation of the roof supports 1 advancing automaticallyone after the other will be described. Although the advancing sequencecan be started at either end of the series, according to whether it isdesired to have the advance sequence proceed from left to right or fromright to left along the series, only a left to right sequence will bedescribed. Before an advance sequence commences, each roof support 1will be set against the roof and the various elements of its valveassembly 10 will be as shown in the drawing.

The control line 12 is first pressurized to 400 lbs/sq. in., but thispressure does not reach chamber 21 because sequence valve 45 is closed.The signal line 15 leading to the left hand side of the secondary valveassembly 14 of the first roof support 1 is pressurized by operation of amanually-operated or remotely-controlled valve (not shown). Thispressure cannot pass non-return valve 37, but opens valve 29 andpressurises line 32. The pressure passes along line 32 through theby-pass valve 39, nonreturn valve 41 and drain valve 42 to the jack 6upon which it acts in a jack-contracting sense. At the same time, thepressure in line 32 actuates piston 59 to pivot lever 57 and open theprop release valve 55 to bring line 54 into communication with the fluidreturn line 30. Hence the props 4 lose their pressure and the roofsupport 1 is released from the roof. The jack 6 then advances the roofsupport 1 up to the conveyor 5.

When the jack 6 is nearly fully contracted, the jack 6 causesprop-resetting valve 46 to pressurise line 47 from line 32. Piston 61then moves lever 57 to allow prop release valve 55 to close, and theprops 4 are reset by pressurisation -of line 47 from line 32. When asatisfactory setting pressure in the props 4 is achieved, this pressurewhich is also present in line 62 opens sequence valve 45 to causepressurisation of chamber 21 and consequent closure of valves 25, 26 andopening of valves 16, 17. Sequence valve 45 is locked in the openposition by fluid trapped in the lines between non-return valves 44, 63and locking valve 64.

The opening of valve 16 results in closure of valve 29 due to fluidpressure from chamber 28 acting on piston 33 in the same direction asthe spring 35. The opening of valve 17 pressurises the signal line 15leading to the adjacent roof support 1 on the right of the roof support1 which has just advanced, and this next roof support 1 then undergoesan advancing operation.

Both valves 29 and 31 are now held in the closed position by fluidpressure from chamber 28 assisting the springs 35, 36 respectively, andline 32 is isolated from the signal lines 15. The pressure in theportion of line 32 between the valves 23, 31 and drain valve 62 andpiston 59 drains away through the restrictor 69. Then the pressure inthe portion of line 32 between the drain valve 42 and the jack 6, andthe pressure in the portion of line 47 between the prop-resetting valve46 and the piston 61, lifts piston valve 66 and drains to the fluid line30.

The advance sequence could equally well proceed from right to left alongthe series, if the signal line 15 leading to the right hand side of thesecondary valve assembly 14 of the roof support at the right hand end ofthe series had been pressurised.

If, during the advance, the roof support 1 met an obstruction and didnot complete its advance, the jack 6 would not operate prop-settingvalve 46. Hence this valve 46 would have to be opened by pressurisationof the control line 12 to 1,200 lbs/sq. in. Safety valve 65 would closeat 800 lbs./ sq. in., and prevent any pressurisation of chamber 21 untilthe pressure in the control line 12 has been reduced back to 400 lbs/sq.in.'

If any of the props 4 develop a leak, the desired setting pressure willnot be achieved in the props 4 and lines 47 and 62 after the roofsupport 1 has advanced. Therefore, there will not be sufiicient pressurein line 62 to operate the sequence valve 45. If this happens, thecontrol line 12 is pressurised to 2,000 lbs/sq. in. to move bypass valve39 to its second position in which signal line 15 and valve 29 areisolated from the jack 6 and props 4 and are brought into communicationwith line 43 leading to the sequence valve 45 which is thus opened.Safety valve 65, which is shut by the 2,000 lbs/sq. in. pressure in thecontrol line 12, opens when the control line pressure is reduced back to400 lbs/sq. in. The chamber 21 is then pressurised by the pressure inthe control line 12, and the pistons 22, 23 are operated by thispressure, and the signal line 15 leading to the next roof support 1becomes pressurized. By-pass valve 39 remains in its second positionbecause of its self-latching property, fluid being trapped in line 43and in the portion of line 32 between halves 29, 31 and by-pass valve39, and hence isolates the leaking part of the hydraulic circuit of theroof support from the signal line 15 and valve 29, thus preventingfurther leakage.

When the by-pass valve 39 of a leaking roof support 1 is moved to itssecond position, the by-pass valves 3% of all the other roof supports 1will be similarly moved. However, the by-pass valves 39 of the otherroof supports will not self-latch, since their lines 32 will not bepressurised.

When all the roof supports have advanced, the locking valves 64 on allthe roof supports 1 are opened by pressurising the control line 12 to2800 lbs./ sq. in. This also causes any operated by-pass valve 39 torevert to the po sition shown in the drawing, since the self-latchingpressure drains away through line 43 and the open locking valve 64 tothe return line 30.

If it is desired to advance the roof supports 1 by manual operation oftheir levers 24, no pressure is put into the control line 12. On anyroof support, manual operation of the lever 24 in an anti-clockwisemanner to operate push-rod 18 causes a signal to be sent along thesignal line 15 leading to the adjacent left hand roof support 1, whichconsequently undergoes an advancing operation. Similarly, manualoperation of the lever 24 in a clockwise manner to operate push-rod 19results in the adjacent right hand roof support 1 undergoing anadvancing operation.

The drain valve 42 also allows fluid to be expelled from the piston rodside of the jack 6 when the conveyor 5 is advanced relative to the roofsupport 1 with consequent extension of the jack 6. When this occurs,fluid from the jack 6 passes up line 32 to the drain valve 42 and movesthe piston valve 66 against the spring 67 to open the pathway to thefluid return line 30.

In an emergency, the props 4 may be reset by manual operation of lever57 and setting valve 58.

We claim:

1. A roof support assembly including a series of advanceable roofsupports, each roof support having at least one fluid-pressure-operatedprop operable to set the support against a roof and afluid-pressure-operated jack operable to advance the support, each roofsupport also having a valve assembly controlling the operation of theprop and the jack, the valve assembly being operated by the receipt of asignal from the preceding roof support in the series to cause its roofsupport to undergo an advancing operation, and the valve assembly beingresponsive to the satisfactory completion of the advancing operation ofits roof support to send a signal to the next roof support in theseries, and by-passing means operable from a position remote from theroof supports to cause the signal to be sent from one roof support tothe next roof support in the event of failure of the roof support tosatisfactorily complete an advancing operation.

2. A roof support assembly according to claim 1 wherein each valveassembly includes a first valve associated with a line which remainsunpressurised until its roof support receives the signal from thepreceding roof support, and operation of the by-passing means actuatesthe first valve of every valve assembly, each valve assembly being soarranged that a first valve actuated by the bypassing means causes thesignal to be sent to the next roof support if the line associated withthe first valve is pressurised.

3. A roof support assembly according to claim 2 wherein each valveassembly includes a second valve operated by a satisfactoryroof-supporting fluid pressure in the prop of its roof support, afterthe roof support has undergone an advancing operation, to cause thesignal to be sent to the next roof support, and the actuation of thefirst valve of a valve assembly when the line associated with the firstvalve is pressurised causes the operation of the second valve of thevalve assembly.

4. A roof support assembly according to claim 2 wherein the signal is afluid-pressure signal which supplies the fluid pressure for the line.

5. A roof support assembly including a series of advanceable roofsupports, each roof support having at least one fluid-pressure-operatedprop operable to set the support against a roof and afiuid-pressure-operated jack operable to advance the support, each roofsupport also having a valve assembly controlling operation of the propand the jack, each valve assembly including an operating line whosepressurisation by fluid under pressure causes operation of the prop andof the jack, and a secondary valve assembly connected by a first line tothe secondary valve assembly of the adjacent roof support in onedirection along the series and by a second signal line to the secondaryvalve assembly of the adjacent roof support in the opposite directionalong the series, each secondary valve assembly including a firstone-Way valve which allows pressurisation of the operating line from thefirst signal line when the first signal line is pressurised from therelevant adjacent roof support and a second one-way valve which allowspressurisation of the operating line from the second signal line whenthe second signal line is pressurised from the other adjacent roofsupport, and valve means responsive to the satisfactory completion ofthe advancing operation of its roof support to hold the first and secondone-way valves in a closed position to prevent pressurisation of theoperating line from either signal line and to connect 7 a source offluid pressure to the first and second signal lines.

6. A roof support assembly according to claim 5 wherein the valve meansincludes two valves which can be manually alternatively operated topressurise either signal line and hold the associated one-way valve in aclosed position.

7. A roof support assembly according to claim 5 wherein pressure in theoperating line drains away when there is no pressure in either signalline and when both oneway valves are held in the closed position.

No references cited.

EDGAR W. GEOGHEGAN, Primary Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.3,272,084 September 13, 1966 Douglas Herbert Hewlett Bolton et a1.

It is hereby certified that error appears in the above numbered patentrequiring correction and that the said Letters Patent should read ascorrected below.

Column 6, line 59, after "first" insert signal Signed and sealed this1st day of August 1967.

(SEAL) Attest:

EDWARD J. BRENNER Commissioner of Patents Edward M. Fletcher, Jr.

Attesting Officer

1. A ROOF SUPPORT ASSEMBLY INCLUDING A SERIES OF ADVANCEABLE ROOFSUPPORTS, EACH ROOF SUPPORTS HAVING AT LEAST ONE FLUID-PRESSURE-OPERATEDPROP OPERABLE TO SET THE SUPPORT AGAINST A ROOF AND AFLUID-PRESSURE-OPERATED JACK OPERABLE TO ADVANCE THE SUPPORT, EACH ROOFSUPPORT ALSO HAVING A VALVE ASSEMBLY CONTROLLING THE OPERATION OF THEPROP AND THE JACK, THE VALVE ASSEMBLY BEING OPERATED BY THE RECEIPT OF ASIGNAL FROM THE PRECEDING ROOF SUPPORT IN THE SERIES TO CAUSE ITS ROOFSUPPORT TO UNDERGO AN ADVANCING OPERATION, AND THE VALVE ASSEMBLY BEINGRESPON-